A. Future statements and nested scopes

The semantics of Python's static scoping will change in version 2.2 to
support resolution of unbound local names in enclosing functions'
namespaces. The new semantics will be available in Python 2.1 through
the use of a future statement. This appendix documents these two
features for Python 2.1; it will be removed in Python 2.2 and the
features will be documented in the main sections of this manual.